Interconnects on elastomers: optimizing for stretchability, speed and layout area

The design of interconnects on elastomers is of interest in flexible electronics. The geometric design of interconnects must take into account the electrical and mechanical aspects, along with layout area. This work discusses the impact of the geometry of stretchable interconnects on various user specifications, namely layout area, stretchability given by mechanical stiffness coefficient and speed given by electrical impedance. Analytical models have been derived and an optimization methodology is developed to help pick the best design for the given application. The analytical models are corroborated with simulations and experiments. Interconnect designs have been fabricated on a copper-viscoelastic adhesive-elastomer stack architecture, using laser toner-transfer process where the viscoelastic adhesive prevents delamination and in which the process flow is in line with conventional printed circuit board fabrication techniques.